Using Rival Effects to Identify Synergies and Improve Merger Typologies

Posted by D. Daniel Sokol

Joseph A. Clougherty and Tomaso Duso (WZB) discuss Using Rival Effects to Identify Synergies and Improve Merger Typologies.

ABSTRACT: The strategic management literature has found it difficult to differentiate between collusive and efficiency-based synergies in horizontal merger activity. We propose a schematic to classify mergers that yields more information on merger types and merger effects, and that can, moreover, distinguish between mergers characterized largely by collusion-based synergies and mergers characterized largely by effi-ciency-based synergies. Crucial to the proposed measurement procedure is that it encompasses the impact of merger events not only on merging firms – as is custom – but also on non-merging competitor firms (the rivals). Employing the event-study methodology with stock-market data on samples of large horizontal mergers drawn from the US and UK (an Anglo-Saxon sub-sample) and from the European continent, we demonstrate how the proposed schematic can better clarify the nature of merger activity.